thompson



(ModeL) J. M.-THOMPSON.

ORE STAMP MILL.

Patented Aug. 2

\NVEN R tial on the face of the die.

UNITED STATES i PATENT OFFICE.

JAMES M. THOMPSON, OF SAN FRANCISCO, CALIFORNIA.

ORE-STAMPYMIILL.

SPECIFICATION forming part of Letters Patent No. 245,030, dated August2, 1881. Application filed April 5, 1880. (ModeL) To all whom it mayconcern:

Be it known that I, JAMES MoNRoE THOMP- SON, of the city and county ofSan Francisco,

and State of California, have invented a new Improvement in. Ore-StampMills; and I do hereby declare that the following is a full and exactdescription thereof.

My invention relates to ore-stamp mills, and my object is to increasetheir efficiency and crush or pulverize a greater amount of ore with agiven-amount of power and number of stamps. The method bywhich 1accomplish the object is to rotate the stamp more rapidly and atthe sametime lift it more quickly than heretofore, so as to allow it to give itsblows faster, and also have more time for. grinding the mate- Itconsists in the employmentofa new combination of the means or devicesfor lifting and at the same time continuously rotating the stamp, and bywhich it is made practicable to increase the rapidity of l its drops orblows by lifting it more quickly, and by which it is also rotated morerapidly, and its crushing-power thereby increased, as more fullyhereinafter explained.

In the accompanying drawings, in which similar letters of referenceindicate like parts,

Figure 1 is a front elevation, showing mortar.

in part section and pinion for rotating the stamps. Fig. 2 is a plan ofthe rotating gearwheels. Fig. ,3 is a plan of the mortar, showingarrangement of the discharging-screens. Fig.4. is aplan of the campartly broken away. Fig. 5 is a face. view of the same.

A is the mortar of atwo-stamp mill, and having the usual openings initsside and ends, over which thevscreens a a are secured, and

through which the pulverized material'is discharged. t Y

B Bare the stamps, and the stamp-stems I) -b have secured to them theusual 'tappets, c c,

and also the pinions ddrwhich engage each other, and the stamp-stemsb bare kept in up- I right position by the guides c c.

C G are sin gle-a-rm cams secured to the horizontal shaft D, which issupported by and rotated in the usual boxes, ff. The boxes ff rest onsprings or buffers g g, and are secured in position. in the usualmanner, except that the holes in their upright flanges, (when they haveany,) as well as those in the upright timbers'h of the frame whichsupports the boxes ff, are elongated, so as to permit them and thecam-shaftD to be depressed at the instant the cam O strikes against theface of the tappet 0. These springs or buffers g gare'for the purpose oflessening the effect of the blows of the cams against the tappets, andalso to prevent theBabbitt metal, with which the boxes ff are usuallylined, from being cracked or broken up by the concussion produced by thesaid blows.

The bevel-gear" wheel '5 is secured to the camshaft D, and engages thebevel-gear wheel is on the lower end of the upright shaft 1, whichissecured to the side ofone of the upright timbers hot the stamp-frame,and the pinion m, which is secured to the upper end of the "uprightshaftl, engages the pinion d on one of the stamp-stems b.

The pinions m and d d are elongated, as shown, so that they will engageeach other all the time during the lifting and dropping of the stamp.

. The cam 0 (shown in Figs. 4 and 5) has formed in its face, at or nearthe part where it strikes thev tappet c, a recess, 02, in which a rubberbuffer, 0, is placed, and the steel or iron strap 12 is secured on andover the buifer and the faceof the cam by the bolt q, near its end andthat of thecam, and by its arm or extension 4-, which projects into therecess tin the hub of the cam in such a manner as to allow its endorpart over the buffer 0 to oscillate, so that when its face strikesagainst the face of the tappet c it will be free to be pressed by theforce of the blow against and compress the spring or buffer 0.

Another method of securing the strap 1) in its position is shown in thesame figure.

s is an arm, which is secured to the strap and extends into the recess ain the face of the cam, through which a hole is made near its end, andalso through the cam, across and near the bottom of recess a, and a key,12, is driven tightly intoand secured by any of the usual means in thehole in the cam, and also passes loosely through the hole in the arm s,the hole being elongated sufficiently to keep the strap 19 (to which itis secured) on (and also allow it when it strikes the tappet tohave freeplay against) the buffer 0. This device can also be used'for securingthe end of the strap 1) at the end of the cam, instead of the bolt q.

To compensate for the metal taken out of the cam by making the recess ain it, its side opposite therecess and next its hub is thickened, sothat the strength of the cam is preserved.

Instead of the rubber buffer 0, a spiral steel spring, or one similar inshape and construction to one-half of an elliptic carriage-spring, andsecured at its center to the under side of the strap 19, and with itsends pressing against the face of the cam, could be employed.

The bevel-gear wheels i and lo and the pinion m are so proportioned intheir diameters in relation to each other and that of the tappet and thelength of the face of the cam C that the periphery of the tappet and theface of the cam will move with as nearly equal speed as possible, sothat there will be less friction and wear of their faces against eachother; and, besides, the force of the blows of the cam against the faceof the tappet will he very much lessened on account of it being keptmoving in the same direction with that of the face of the cam.

'lhe pinions d d are secured to the stampstems Z) by any of the usualmeans, and springpawls w, secured in them, engage the ratchet y in thestamp-stem in such a manner as to al' low the pinions to be forcedupward on the stamp-stems (when required by the wearing away of theshoes and dies) by placing a stop on the top of the guide 0, on which(when the stamp falls) the lower end of the pinion will strike and bedriven up on the stamp-stem, the pawl and ratchet permitting it to moveup, but preventing it from being forced down on the stamp-stem by theblows of the stamp, so that the pinions can be forced upward on thestampstcms as the shoes and dies wear away without stopping theoperation of the mill. These pinions dd could be secured to thestamp-stems b 1) below instead of above the upper guides, 00, and usedto supply the place of the tappets c 0, in which case there would be twoof them on the stamp-stem next the shaft 1,- also, instead of beingkeyed or secured to the stampstems b b and moving up and down with them,the pinions d (I could have round hollow central arms or shaftsextending downward into and secured and rotating in the upper guides ce, and not move up and down with the stampstems b b, and the usual meansof a key or feather and groove employed to cause the pinions to rotatethe stamp-stems, in which case the pinions need not he elongated, asshown in the drawings. I, however, prefer the clongated pinions, andsecured to the stamp-stems, as shown and herein described, as therebymuch friction and loss of power are saved, for the pressure of the teethof the pinions against each other is much less than that of keys orfeathers would be against the sides of grooves in the pulleys.

The operation of my improved stamp-mill is similar to the ordinarystamp-mill, the stamps 65 B B being lifted by the cams C C in the usualmanner; but, in addition to being lifted, the

stamps B B are also continuously rotated by the bevel-gear wheelt' onthe cam-shaft D, the bevel-gear wheel It and pinion m on the uprightcounter-shaft l, and the pinions d d on their stems in such a direction,and the cams O O are secured in such positions on the camshaftD andsides of the stamp-stems b b, as to cause the faces of the tappets andcams to move together and at approximately the same speed.

By continuously rotating the stampstems in H such a direction and withsuch aspeed, and securing the cams in such positions on their shaft asto cause the faces of the tappets and cams to move in the same directionand at the same approximate speed, the force of the con cussion producedby the striking of the cams against the faces of the tappets is verymuch reduced; also, by the single cam, in combi= nation with the meansherein described for retating the stamps, an increased grinding effectis obtained above that produced by the rotation of the stamps in anyother rotating stampmill, (of which I have any knowledge,) because ofthe rotation of the stamp being much more rapid, it being nearly threetimes during one drop, while in those mills in which the stamp is raisedby its rotation, or in those where double cams have been tried, there isand can be practically but one revolution of the stamp to each drop,unless the stamps were rotated at such speed as to cause the faces ofthe tap-' pets to rotate or travel faster than the faces of the cams,which would cause much friction and soon wear away the faces of the camsand tappets.

The increased speed at which the stamp can be rotated when a single cam,in combination with the other devices described, is employed for liftingand rotating it is because the shaft of a single cam can be rotatedthree times as fast as that of a double cam and allow the stamp the sametime for dropping, and therefore the face of a single cam can travelthree times as fast as that of a double cam and as the stamp-stem (inorder to avoid too much wear, as before explained) must be rotated withsuch speed as to cause the faces of the tappets to move withapproximately the same speed as the faces of the cams, it follows thatwith the combination of a single cam with the rotating mechanismdescribed the stamp can be rotated three times as fast as it couldpractically be rotated with a double cam.

It has heretofore been attempted to rotate stamps continuously whilebeing lifted independently by double cams; but, owing to the stamp-stemsand tappets being rotated faster than the speed of the faces of thedouble cams, there was found to be too much friction and loss of power,and the experiment was abandoned. Besides,if the speed of the faces ofthe tappets and cams had been made equal, although much of the increasedfriction and wear would have been avoided,'yet there would have been butvery little increase of the crushing or grinding effect of the stampproduced by such a slow rotation and, also, there being three times asmuch time required for lifting the stamp witha double cam as with asingle one, there could be but very little time given the stamp to twiston or grind the material between its face and that of the die,'so that,rotating only one-third as fast and being less time in contact with thedie, there would be very little gained by its rotation at all, unlessthe number of the drops per minute were materially decreased, whichwould then decrease the crushing effect of the stamp more than itsgrinding eflect would be increased; and it would not be practicable toincrease the num-v ber of drops and rotations of the stamp by the use ofa single cam without the means herein shown and described (or othermeansnotknown tome) of lessening the effect. of the. blows of the camagainst the tappet.

I do not broadly claim continuously rotating a stamp while being liftedor dropped; nor do I claim lifting a stamp by means of its rotation, asthat is covered by patents heretofore granted; but my invention embracesan im- 7 proved means for rotating the stamp in such a direction and atsuch a speed as'to cause the faces ofthe tappets and cams to move witheach other and at the same approximate speed when in contact with eachother, for the purpose not only of avoiding as much friction and wear aspossible, but also of decreasing the force of the concussion produced bythe blow of the cam against the tappet, as well as to increase thegrinding efl'ect of the rotation of the stamp, which'last improvedresult is obtained by the use of the single-arm cam in combination withtheother devices described, as before explained; It also embraces theelastic cam formed as herein described, as an additional means forlessening the effect of the blows of the cam against the tappet; and,also, the combination of the rubber or elastic seats 9 g with the boxesin which the cam-shaft rotates, as a further means of lessening thesame,

as well as also to .prevent the cracking or breaking of the Babbittmetal in said boxes by the concussion.

My invention also embraces the use of a single can], in combination withthe herein-described devices, (for rotating the stamp andlessening theviolence or effect of the concussion produced by the blow of the camagainst the tappet,) for the purposes of increasing the number of thedrops of the stamp per minute (and with the same height of drop) overthat which can be made with a double cam fully one-half, and ofincreasing the rapidity of the rotation of the stamp, and which wouldnot be practicable with the use of a single cam without also thecombination with it of the said devices, as, in order to increase therapidity of the drops of the stamp fifty per cent. over that produced bya double cam, the shaft of a single cam must rotate three times as fastas that of a double cam,"and the blow will consequently be very muchgreater.

Having thus described my invention, what I claim is-- 1. In a rotatingstamp mil], the automatically-shiftin g elongated pinions d d, havingsecured tothem the spring-pawl w; in combination with the ratchet yinthe stamp-stems b b, substantially as described.

2. In a stamp-mill, the combination, with the Cam 0, of the strap 10 andthe buffer or spring 0, substantially in the manner and for the purposedescribed.

3. In a stamp-mill, the cam-shaft D, in combination with its bearings orboxes f f, which rest on the rubber or elastic springs g g, and with itscams O O, which are secured to it, and having in combination with themtheir straps p p and buffers or springs 0 0, substantially as and forpurposes described.

JAMES MONROE THOMPSON.

Witnesses:

, V E. D. J UDD,

.F. E. MONTEVERDE.

